不同紫花苜蓿杂交组合对冻害胁迫的生理响应

冻害是紫花苜蓿(Medicago sativa)在东北地区种植的主要限制性因素,筛选能够抵御冻害胁迫的育种材料,对于提高紫花苜蓿的产量和品质有重要意义。本研究选用5种不同紫花苜蓿杂交组合为试验材料,3个阶段处理,即抗寒锻炼阶段、冷冻阶段以及返青阶段,测定其可溶性蛋白(SP)、可溶性糖(SS)、脯氨酸(Pro)、丙二醛(MDA)含量以及超氧化物歧化酶(SOD)活性。结果表明,随3阶段处理SP的含量总体呈现升高的趋势,且每个材料返青阶段的含量均显著高于对照组,并达到最大值(P0.05);SS的含量总体呈先降低后升高再降低的趋势,冷冻阶段的SS含量显著高于对照组且达到最大值;Pro含量总体呈升高趋势;Ⅱ、Ⅲ、Ⅴ杂交组合MDA含量低于对照组,但降幅不显著(P0.05),其余各阶段含量均显著高于对照组,且返青阶段达到最大值;SOD活性总体呈先升高后降低的趋势,且冷冻阶段含量显著高于对照组达到最大值。采用隶属函数法综合评价各杂交组合的抗寒性,由强至弱的顺序是ⅤⅢⅠⅡⅣ。

Physiological responses of different alfalfa hybrid combinations to freezing stress

Freezing inj ury is the main limiting factor for alfalfa in northeast China.The screening of breeding materials that can resist freeze—thaw stress is of great significance for improving the yield and quality of alfal-fa.In the present study,five different combinations of alfalfa(Medicago sativa)were selected as test materi-als,which were subj ected to three different treatment stages:cold resistance training stage,freezing stage,and turning green stage.soluble protein(SP),soluble sugar(SS),proline(Pro),and malondialdehyde(MDA)con-tents,and superoxide dismutase(SOD)activity were measured.The results showed that the SP content had an overall increasing trend and was significantly higher in each test material than in the control group.The SS con-tent fluctuated and was significantly lower in all test materials than in the control group during the cold resist-ant stage.The SS content was significantly higher in all test materials than the control group during the frozen stage,and the Pro content generally increased.MDA contents in the Ⅱ,Ⅲ,and Ⅴ hybrid combinations were lower than that in the control group,although this difference was not significant.SOD activities first increased and then decreased,with the contents during the other phases significantly higher than that in the control group.Membership function analysis showed that the order of cold resistance in the hybrid combinations wasⅤ>Ⅲ>Ⅰ>Ⅱ>Ⅳ.